DE102005033087A1 - Method and device for avoiding rear-end collisions - Google Patents

Abstract

method and device for avoiding rear-end collisions when starting behind a preceding vehicle, wherein by means of a in the vehicle apron aligned environment sensors of the distance and / or speed is determined to the preceding vehicle and if present a starting situation evaluated a driver-actuated longitudinal dynamics default is whether a risk of collision of the vehicle with the vorausbefindlichen Vehicle exists, and in the presence of a risk of collision in the Drive train and / or the delay devices intervention of the vehicle to reduce the risk of collision, and / or driver warning devices are driven to the driver over the Risk of collision.

Description

The The present invention relates to a method and an apparatus to avoid rear-end collisions when starting behind a preceding vehicle, by means of a in the vehicle apron oriented environment sensors of Distance and / or the speed to the preceding vehicle is determined and in the presence of a starting situation, a driver-actuated longitudinal dynamics default is evaluated, whether a risk of collision of the own vehicle is present with the preceding vehicle and if present a risk of collision in the drive train and / or the deceleration devices the vehicle is intervened in order to reduce the risk of collision and / or Driver warning devices are controlled to the driver on the Risk of collision.

From the DE 102 18 017 A1 is a method for speed and distance control in motor vehicles is known in which the distance of a preceding vehicle is measured and the distance control at least two operating modes are provided which can be activated in different overlapping speed ranges, and wherein the switching between these operating modes at least in one direction only by a driver command, wherein the speed of the preceding vehicle is extrapolated into the future based on the speed of the own vehicle and the measured distance and / or relative speed data and that a shift request is issued to the driver when the extrapolated speed is outside the allowable range for the current mode and the current speed are within the allowable range for the other mode.

Core and advantages the invention

The essence of the present invention is to provide a method and a device with which the risk of rear-end collisions when approaching behind a preceding vehicle can be avoided by a risk of collision is determined and depending on the degree of risk of collision in the drive train and or the deceleration devices of the vehicle is intervened in order to avoid excessive acceleration of the vehicle and the driver is informed by means of a driver warning device on the increased risk of collision. In this case, a starting situation can be recognized by the fact that the vehicle ahead was detected as stationary by means of the environmental sensor system and an acceleration of the own vehicle is measured in the subsequent measuring cycles. By evaluating the longitudinal dynamic specifications of the driver, which is derived from the instantaneous accelerator pedal actuation angle and the instantaneous brake pedal actuation angle, a collision risk can be determined with the aid of the instantaneous distance d and the instantaneous relative speed v _rel . In this case, intervention in the drivetrain control by the accelerator pedal characteristic is reconfigured for example, so that at a certain accelerator opening angle α _FP a lower acceleration request is issued, as in the usual driving operation that angle α _FP is associated. This results in a lower acceleration request to the vehicle, whereby at an increased risk of collision, the vehicle is accelerated less than the driver is used to from the usual driving. The intervention in the deceleration devices of the vehicle may be configured such that a brake pressure build-up of the wheel brakes is automatically built up and controlled, so that the vehicle acceleration is simultaneously braked by the accelerator operation of the driver to prevent an excessive acceleration of the own vehicle at an increased risk of collision. Furthermore, it can be prevented by the automatic brake pressure build-up that when starting on a slope, the own vehicle rolls away when the driver does not press the accelerator pedal in time or accelerates the vehicle less than the driver is used to from the other driving situations, because at the same time the accelerator characteristic is reparameterized. Furthermore, the driver can be informed about the increased risk of collision, for example by activating audible or visual warning devices or by using, for example, an accelerator pedal with active restoring force, in which the resistance of the accelerator pedal is electrically controllable. In the case of an increased risk of collision, it is possible here to increase the restoring force of the accelerator pedal F _FP , so that the driver feels an increased back pressure on the accelerator pedal, whereupon he intuitively reduces the accelerator pedal actuation angle α _FP , so that the risk of collision is reduced. According to the invention this is achieved by the features of the independent claims. Advantageous developments and refinements emerge from the subclaims.

advantageously, a starting situation is detected when the own vehicle off accelerates the standstill and the own vehicle speed is below a predetermined limit speed.

Furthermore, it is advantageous for the environment sensor system to be an ultrasound sensor, a radar sensor, a lidar sensor, a photonic mixing device (PMD) sensor, a video sensor or a combination of these types of sensors.

Farther it is advantageous that the driver-actuated longitudinal dynamics default is an accelerator pedal operation and / or releasing the brake pedal.

Advantageously, the intervention in the drive train of the vehicle by a change in the accelerator pedal characteristic. The accelerator characteristic here is the assignment of an acceleration request or an engine torque demand as a function of the currently set accelerator pedal angle α _FP , wherein in this Anfahrsituation the characteristic can be changed such that at the same accelerator pedal angle α _FP a lower acceleration request or a lower engine torque request is issued than it is provided in the usual driving.

Farther It is advantageous that the intervention in the deceleration devices by an automatic brake pressure build-up, in order to prevent a collision-endangering, driver-operated Start to complicate.

Advantageously, the intervention takes place in the deceleration devices by an automatic brake pressure build-up to prevent a rolling back of the own vehicle when starting on a slope. The rolling back of the own vehicle when starting on a slope can be favored that the accelerator pedal characteristic has been reparameterized so that at a certain accelerator pedal angle α _FP a lower acceleration request or lower engine torque request is issued, as provided in the usual driving, whereby when starting on Berg can be so low by this Umparametrierung the actually requested acceleration or engine torque requirement that a rolling back of the own vehicle threatens without the driver is prepared for it. In particular, the combination of the Umparametrierung the accelerator characteristic with the automatic brake pressure build-up has the consequence that even in this Anfahrsituation on a slope of the following road users is not more at risk than without the inventive system. In order to be able to detect a start on the mountain, a longitudinal acceleration sensor can be provided, which provides a longitudinal acceleration signal a _x . Optionally, the longitudinal acceleration a _{x can} also be used from a time derivative of the relative speed of objects that were detected by the surroundings sensor as standing objects.

Furthermore, it is advantageous that the driver warning by means of an accelerator pedal with electrically controllable restoring force, wherein at an increased risk of collision, the restoring force F _{FP of} the accelerator pedal is increased. Such danger pedals are already available on the market and are known, inter alia, under the name force feedback pedal.

Farther it is premature that the driver warning device an audible Signaling device, for example in the form of a text output or provided in the form of a buzzer. In addition to the acoustic signaling device or alternatively, it is also possible an optical driver warning device provided by, for example, a warning light is activated or a plain text output appears on the display of the dashboard becomes.

advantageously, the driver can by an accelerator override the collision avoidance function disable at any time.

Farther it is advantageous that the collision avoidance function only below an upper limit speed is active. As upper limit speed is for example a speed threshold between 10 km / h and 20 km / h imaginable, since at higher speeds of a normal driving operation can be assumed and the starting process is completed.

Farther it is advantageous that the collision avoidance function by a driver intervention in the drive train by oversteer the accelerator pedal and / or driver intervention in the deceleration devices by operation the brake pedal is deactivated. As a result, the driver has at any time the possibility by deliberately depressing the accelerator pedal or the brake pedal to override this collision avoidance function and the vehicle continue according to his individual specifications.

Of particular importance is the realization of the method according to the invention in the form of a control element which is provided for a control device of a distance control or cruise control of a motor vehicle. In this case, a program is stored on the control, which is executable on a computing device, in particular on a microprocessor or signal processor, and suitable for carrying out the method according to the invention. In this case, therefore, the invention is realized by a program stored on the control program, so that this provided with the program control in the same way is the invention as the method to whose execution the program is suitable. In particular, an electrical storage medium may be used as the control, for example a Read-only memory.

Further Features, applications and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, which are illustrated in the figures of the drawing. All described or illustrated features form for themselves or in any combination, the subject matter of the invention, regardless of their summary in the claims or their dependency as well as independently from their formulation or presentation in the description or in the drawings.

drawings

following Be exemplary embodiments of Invention explained with reference to drawings. Show it

1 a schematic block diagram of an embodiment of the device according to the invention and

2 a flow diagram of an embodiment of the method according to the invention.

description of exemplary embodiments

In 1 a schematic block diagram of a device according to the invention is shown. Evident is the collision warning and avoidance device 1 that have an input circuit 2 by means of the collision warning and avoidance device 1 Input signals can be fed. As input signals are the input circuit 2 Output signals of an environment sensor 3 which can be embodied, for example, as an ultrasonic sensor, as a radar sensor, as a lidar sensor, as a video sensor, or as a combination of these types of sensors. This environment sensor 3 is oriented so that the vehicle's front-end environment is detected and objects located therein, such as preceding vehicles or preceding, stopped vehicles are detected and their distance d to their own vehicle and their relative velocity v _{rel is} determined. Furthermore, it is possible to have a sensor 3 which can detect an azimuth angle at which the preceding object was detected. These object-related measured variables are determined by the environmental sensor technology 3 to the input circuit 2 passed. Furthermore, a speed sensor 4 provided, which detects the current speed of the own vehicle and as a measured variable v _Fzg also to the input _circuit 2 the collision warning and avoidance device 1 supplies. Another input is the input circuit 2 the accelerator pedal actuation angle α _{FP is} supplied, which indicates the extent to which the accelerator pedal 5 has been deflected by the driver and thus can be assigned an acceleration request or an engine torque request. Furthermore, the input circuit 2 a brake pedal operating angle α _{BP of} the brake pedal 6 indicating the extent to which the brake pedal has been deflected by the driver or whether the driver is depressing the brake pedal 6 currently not activated. Furthermore, it can be provided that the input circuit 2 as a further input signal, the longitudinal acceleration a _{x of} the own vehicle is supplied, whereby a standing or starting on a slope can be detected. For this purpose, a longitudinal acceleration sensor 21 be provided. Alternatively, however, this information can also be determined by time derivative of the relative speed of stationary objects, for example, at the roadside, by means of the environment sensor. The input circuit 2 supplied input signals are by means of a data exchange device 7 a calculation device 8th supplied, which may be embodied for example as a microprocessor. The calculation device 8th includes a program that executes the method according to the invention in the form of control information and that depending on the input circuit 2 supplied input signals calculates output signals that are output to downstream actuators. These output signals are from the computing device 8th by means of the data exchange device 7 to an output circuit 9 output to which the downstream actuators are connected. As a control element that affects the drive train of the vehicle, is a performance-determining actuator 10 an internal combustion engine, which may be embodied, for example, as an electrically controllable throttle valve or fuel quantity measuring device in the form of an injection valve and which regulates the internal combustion engine depending on the driver requested acceleration request or engine torque request. Another actuating element is the delay device 11 of the vehicle provided, for example, has an electrically controllable brake booster and one of the output circuit 9 output signal converted into a corresponding brake pressure or a vehicle deceleration and the vehicle automatically performs a delay in dependence on the brake pedal actuation angle α _BP or independent of a driver actuation. This makes it possible for the collision warning and avoidance device 1 in the delay devices 11 the vehicle can intervene. As a further control element is a driver warning device 12 provided, which may be embodied for example as an acoustic and / or optical Sinaleinrichtung, for example in the form of a flashing warning light, a plain text display in the display of the vehicle dashboard, as a warning buzzer or in the form of a machine text output via a loudspeaker. Another option for informing the driver of an increased risk of collision is an active accelerator pedal 5 are provided, which can generate an electrically adjustable restoring force, whereby the counter-force of the pedal is adjustable against the driver's foot. By outputting a control signal F _FP through the output circuit 9 it is possible the restoring force of the accelerator pedal 5 adjust accordingly and thereby signal to the driver that he should press the accelerator pedal less. This makes it possible for the driver not only acoustically or optically by means of the signaling device 12 but also to influence the driver intuitively or alternatively in addition to the feeling of pressure in the foot in order to communicate a risk of collision and to reduce the risk of collision.

In 2 a flowchart of the method according to the invention is shown. This process starts in step S13 and continues in step S14, where it is checked whether a starting situation has been detected. The starting situation can be recognized by the environment sensors 3 a preceding vehicle was detected which is at a standstill. If it is then determined that the own vehicle is accelerated, eg by requesting an engine torque, and is no longer at a standstill, then a starting situation is detected and step S14 branches to "yes." If no starting situation is detected in step S14, then the flowchart branches after "no" and is ended in step S20. If a starting situation was detected in step S14, the flowchart in step S15 is continued by the speed sensor 4 determined vehicle _speed v _{Fzg is} checked whether this is greater than a predetermined limit speed v _limit . The limit speed v _limit here represents an upper speed threshold up to which the method according to the invention is active. If the own vehicle speed V _{Fzg is} above the upper limit speed V _limit , which may be, for example, between 10 km / h and 20 km / h, then it is assumed that there is no longer a starting situation and normal driving exists. If it has been detected in step S15 that the instantaneous vehicle speed v _{Fzg is} greater than this limit speed v _limit , then the method branches to "yes" and is ended in step _{S 20. It} was recognized that the vehicle speed _{V Fzg} is less than or equal to the limit speed _V limit Thus, the process proceeds to step S16, in which the measured values for the distance d of the detected preceding vehicle to the own vehicle, the relative velocity v _{rel of} the preceding vehicle with respect to the own vehicle, the current accelerator pedal angle α _FP and the current brake pedal operation angle α _BP determined and in the calculator 8th are processed. By means of the accelerator operating angle α _FP , α _BP , it is possible to determine whether the driver has released the brake pedal and actuates the accelerator pedal, so would like to start his own vehicle and how much he wants to accelerate their own vehicle to start and how fast that preceding vehicle removed by the distance d and the relative velocity vrel are evaluated. From the values relating to the driving dynamics of the vehicle ahead as well as the driver request signals α _FP and α _BP a collision risk is calculated in the following step S17, for example, by how much time remains until a potential collision with the vehicle ahead would be if their own Vehicle would continue to operate with the current acceleration requirements. However, it is also conceivable to detect a risk of collision by means of other algorithms, for example by depositing multidimensional tables which _assign corresponding collision risk values to the corresponding measured values d, v _rel , α _FP and α _BP . In the following step S18, several measures S18a to S18d are listed, whereby, depending on the embodiment of the invention, only one of these measures S18a to S18d can be executed, any combination of these measures can be executed or all the described measures S18a to S18d can be carried out together. Thus, according to S18a, it is provided that the accelerator characteristic is reparameterized in dependence on the risk of collision ascertained in step S17, so that at a specific accelerator pedal angle α _FP an acceleration request or engine torque request is output which is lower than at the same accelerator pedal angle α _FP in the conventional driving mode. According to step S18b, alternatively or in combination with step S18a, it is possible to build up an automatic brake pressure build-up in accordance with the collision danger calculated in step S17 so that the vehicle is accelerated less by the accelerator operation of the driver since the vehicle deceleration devices 11 act against the acceleration request or when starting on a slope a rolling back of the own vehicle is avoided. According to step S18c, which may be provided as an alternative to the steps S18a and S18b or in any combination with these, an output of a driver warning is provided by an acoustic and / or optical signaling device 12 the driver points to the existing risk of collision. According to step S18d, it is possible, optionally or alternatively to the described steps S18a to A18c, to output a desired value F _FP representing an accelerator pedal restoring force with which the active accelerator pedal presses against the driver's foot to signal the driver that he is depressing the accelerator pedal 5 deflect less than it currently does to reduce the existing collision hazard calculated according to step S17. In the subsequent step S19 it is checked whether the driver reacts by an accelerator pedal operation or a brake pedal operation on the existing risk of collision and wants to override the system by a strong acceleration request or a strong deceleration request and thus would like to override the collision warning and avoidance device. If it has been detected in step S19 that driver override exists, then step S19 branches to "yes" and the method is ended in step S20, so that a normal driving operation is transited. If it is detected in step S19 that there is no driver override request, then branches Step S19 to "no" and the process returns to step S15, where it is again checked whether the activation condition exists that the own vehicle _speed V _{Fzg may} not be greater than the predetermined limit speed v _limit and the process is run through again, so that the output values for implementing the actions according to steps S18a to S18d can be adjusted to the new traffic situation with newly read measured values d, v _rel , α _FP , α _BP .

Claims (14)

Device for avoiding rear-end collisions when starting behind a preceding vehicle, wherein by means of an environment sensor system oriented in the vehicle apron ( 3 ) the distance (d) and / or the speed (vrel) to the vehicle ahead is determined and in the presence of a starting situation a driver-actuated longitudinal dynamic specification (α _FP , α _BP ) is evaluated, if there is a risk of collision of the own vehicle with the vehicle ahead, characterized in that in the presence of a risk of collision in the drive train ( 10 ) and / or the delay devices ( 11 ) of the vehicle is intervened in order to reduce the risk of collision and / or driver warning devices ( 12 . 5 ) to inform the driver about the risk of collision. Device according to claim 1, characterized in that that a starting situation by pressing the accelerator pedal by the driver is recognized. Apparatus according to claim 1 or 2, characterized in that a _{starting situation} is only detected when the own vehicle speed (v _Fzg ) is below a predetermined limit speed (v _limit ). Device according to one of the preceding claims, characterized in that the environment sensor system ( 3 ) is an ultrasonic sensor, a radar sensor, a lidar sensor, a video sensor or a combination of these types of sensors. Device according to one of the preceding claims, characterized in that the driver-actuated longitudinal dynamic specification is an accelerator pedal actuation (α _FP ) and / or a release of the brake pedal (α _BP ). Device according to one of the preceding claims, characterized in that the engagement in the drive train ( 10 ) of the vehicle is effected by a change in the accelerator characteristic. Device according to one of the preceding claims, characterized in that the intervention in the deceleration devices ( 11 ) is carried out by an automatic brake pressure build-up to complicate a collision-risky, driver-actuated starting. Device according to one of the preceding claims, characterized in that the intervention in the deceleration devices ( 11 ) is carried out by an automatic brake pressure build-up to prevent a rolling back of the own vehicle on a slope. Device according to one of the preceding claims, characterized in that the driver warning ( 5 ) by means of an accelerator pedal ( 5 ) with electrically controllable restoring force (F _FP ), wherein at an increased risk of collision, the restoring force (F _FP ) of the accelerator pedal is increased. Device according to one of the preceding claims, characterized in that the driver warning device ( 12 ) is an acoustic signaling device. Device according to one of the preceding claims, characterized in that the driver by an accelerator pedal override ( 5 ) can disable the collision avoidance function. Device according to one of the preceding claims, characterized in that the collision avoidance function (V _limit) is active only below an upper limit speed. Device according to one of the preceding claims, characterized in that the collision avoidance function by a driver intervention in the drive train ( 10 ) is deactivated by overriding the accelerator pedal (α _FP ) and / or a driver intervention in the deceleration devices by actuation of the brake pedal (α _BP ). A method for avoiding rear-end collisions when starting behind a vehicle ahead, wherein as a function of the distance (d) and / or the speed (vrel) to the vehicle ahead, which by means of an environment sensor ( 3 ) is determined, and in the presence of a starting situation, a driver-actuated longitudinal dynamic specification is evaluated whether a risk of collision of the own vehicle with the vehicle ahead, characterized in that in the presence of a risk of collision in the drive train ( 10 ) and / or the delay devices ( 11 ) of the vehicle is intervened in order to reduce the risk of collision and / or a driver warning ( 12 . 5 ) is issued to inform the driver about the risk of collision.